This invention relates generally to dust seals on drilling machines, and more particularly to dust seals on drilling machines that are tiltable for angle drilling.
The practice of drilling angled blast holes for surface mining has become quite popular. Blast holes are drilled at angles of up to 30 degrees (from the vertical). One of the primary advantages of this technique is that the blast itself will move some material which overlays the ore being mined, thereby leaving less material to be moved by shovels.
Drilling angled blast holes has created new problems when it comes to containing the dust which is produced by the process. On those drills which have a platform through which the drill pipe and bit must pass, it is necessary to maintain a fixed orientation of the dust seal assembly relative to the centerline of the drill pipe to maintain effective sealing This requirement is further complicated by the fact that a given drill rig may drill at several different angles in the course of drilling a particular area to be mined. Therefore, the means of orienting the seal assembly must be easily adjustable.
Finally, on some occasions, water will be encountered when drilling a blast hole. The air which flushes the cuttings out of the hole will also flush the water. This airborne water and dust can become packed in any type of mechanical linkage and render it inoperative.
The foregoing illustrates limitations known to exist in present dust seals. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.